eusporangiate

Eusporangiate is a term used in botany to describe a type of sporangium development found in certain groups of vascular plants, most notably ferns, horsetails, and lycophytes. This developmental pathway is contrasted with leptosporangiate development. In eusporangiate development, the sporangium originates from a group of initial cells in the epidermis or subepidermis. These cells divide periclinally and anticlinally to form a multicellular jacket and a central mass of sporogenous cells. This leads to the production of a large number of spores. The sporangium wall in eusporangiate types is typically composed of multiple cell layers, although in some groups, it may become a uniseriate layer at maturity. The tapetum, which nourishes the developing spores, is also derived from the initial cells and is often parietal and sometimes absorbed during spore maturation. Eusporangiate sporangia are generally larger and produce a greater number of spores compared to leptosporangiate sporangia. This developmental mode is considered to be more primitive.